An organic EL (Electroluminescence) display device is characterized by its (i) low power consumption which is lower than that of a cathode ray tube (CRT) and is equivalent to that of a liquid crystal display (LCD), (ii) high image quality, and (iii) wide viewing angle. Because of these characteristics, the organic EL display device has been the focus of attention.
In general, an organic EL element used in an organic EL display device is configured such that organic material is vertically sandwiched between electrodes (anode and cathode). In such an organic EL element, holes and electrons are injected from the anode and the cathode, respectively, into an organic layer made up of the organic material. In the organic layer, the holes and the electrons are recombined. This causes light emission.
With such an organic EL element, non-radiative points called dark spots may be generated if the organic layer becomes crystallized due to entrance of moisture or oxygen etc. into to the organic EL element. The dark spots are known to grow over time and the growth of the dark spots is known to reduce the life span of the organic EL element. Hence, when producing an organic EL display, it is necessary to suppress entrance of moisture and oxygen etc. into an organic EL element as much as possible.
Under such circumstances, some organic EL display devices are each configured to seal an organic EL element by (i) covering, with a sealing resin, a display region on an element substrate such as a glass substrate which is provided with the organic EL element and (ii) combining a sealing substrate (such as glass substrate) to the element substrate so that the sealing substrate faces the element substrate and the sealing resin is sandwiched between the element substrate and the sealing substrate. In an organic EL display device having such a configuration, generally, an ultraviolet curable resin or a thermosetting resin is used as a sealing resin and such a sealing resin is cured after the sealing substrate is attached. The organic EL element is driven in response to a drive voltage applied thereto via external electrodes and external terminals which are provided around the display region.
For example, Patent Literature 1 discloses a configuration like above.
FIGS. 6A-C depict explanatory views schematically illustrating an organic EL display device and a method for producing the organic EL display device which are disclosed in Patent Literature 1.
As illustrated in FIGS. 6A-C, the organic EL display device is configured such that an element substrate 101 and a sealing substrate 103 are bonded together so as to face each other via a sealing resin 102 for sealing a display region. In such an organic EL display device, a protection wall (sealing part) 107 for separating the display region from an electrode region is provided between the element substrate 101 and the sealing substrate 103.